Clathration process



Dec. 15, 1964 w. D. scHAx-:FFER

CLATHRATION PROCESS Filed April 17. 1961 Umted States Patent Olice 3,l6i,694 Patented Dec. l5, 1964 This invention relates to a method for separating difcully separable compounds such as isomers or the like by selective clathration, and particularly to the preparation of stable solutions for use in such selective clathration processes.

In one sense, the present invention can be viewed as an improvement in those clathration systems which employ aqueous alkaline solvent media in the clathration and/or declathration steps, and especially wherein liquidliquid phase separations are relied upon for recovering the clathrated and nonclathrated feed components from the aqueous alkaline media. Three such clathration systems are described in my copending U.S. applications Serial No. 362,223, tiled December 28, 1959 and maturing into U.S. Patent No. 3,043,892 on July 10, 1962; Serial No. 3,058, tiled January 18, 1960 and maturing into U.S. Patent No. 3,049,575 on August 14, 1962; and Serial No. 26,489, tiled May 3, 1960 and maturing into U.S. Patent No. 3,029,300 on April 10, 1962.

One of the preferred Werner complexes for use in the processes of said copending applications is nickel tetra(4 methylpyridine)dithiocyanate for reasons made clear in those applications. Hereinafter, for simplicitys sake and in accordance with customary practice in the industry, 4methylpyridine will be abbreviated as 4MP, and nickel tetra(4methylpyridine)dithiocyanate will be identilied as N(4MP)4(SCN)2. I shallalso refer to the two portions of the Werner complex as the Werner amine (such as 4MP) and the Werner salt (such as Ni(SCN)3). In the clathration process the Werner complex is preferably ud as a solution in a primary solvent, which in th e case of the above patent applications consists essentially of water, an alkali such as ammonia or an alkanolamine,

Salt.

wand,insomeinstances,abulersa1tsuchasanammonium The invention is of utility for clathration processes using clathration solutions in which the Werner 'salt is Ni(SCN), the Werner amine is 4MP, the alkali is ethanolamine (MEA) and the buler salt is ethanolammonium thiocynate (MEA-HSCN) and for purposes of clarity andsimplicity of explanation it will lirst be considered here in suchY limited form. `However, as will be made clear hereinafter, the methodis substantially broader than this with respect to operable classes of Werner complexes, aqueous alkaline solutions and buier salts.

A preferred Werner complex solution Within the scope of this invention comprises a 25 percent solution of Ni(4MP)4(SCN)2 in a primary solvent of the following composition:

Component: f Weight percent Water n 45 Ethanolamine 38 Ethanolammoniunthiocyanate 17 Nickelous thiocyanate is not comlnercially available as such and heretofore it has been the practice to prepare solutions of N(4MP)4(SCN)2 by preparing the Werner complex in a separate operation, then air drying it and adding it to a suitable primary solvent. The conventional method of preparing Ni(4MP)4(SCN)2, prior to my invention, was to add 4-methylpyridine to an aqueous solution of nickelous sulfate and ammonium thiocyanate.

This technique yields the water insoluble complex as a hydrous precipitate containing 30 to 50 weight percent water. Customarily, this hydrous compound has been air dried before use as a clathrate former in Werner com plex solutions. The overall reaction of this process of Werner complex formation is illustrated by the following formula:

In isolating and air drying Ni(4MP)4(SCN)2 prepared according to the above-described method, some of the 4- methylpyridine is invariably lost frenir .the complex. Furthermore, the nal product is contaminated with (Nl-102804, the lay-product of the subject method of synthesis, which cannot be completely washed out.

In accordance with this invention the Werner complex solution is prepared by rst preparing a solution, stable to storage, of nickelous thiocyanate and alkanolammonium thiocyanate, such as, for example, ethanolammonium thiocyanate, useful as an intermediate in the preparation of Werner complex solutions such as those described above. The solution of nickelous thiaocyanate and alkanolamminoum thiocyanate can be readily converted to a Werner complex solution suitable for clathration purposes by adding a/fWerneramine, such as 4-methylpyridine, thereto, along with any additional solvent ingredients which might be required to adjust the iinal solution to a desired composition.

It will be readily apparent to those skilled inthe art that the preparation ofl a Werner complex clathration solution from the nickelous thiocyanate-alkanolammonium thiocyanate -solution`of this invention affords a simple and practical means of obtaining such free ofcontaminating ammonium 'and sulfate ions. Furthermore, the preparation. of Werner complex solutions in this manner completely avoids the intermediate steps of isolating and drying solid Werner complexes (and the attendant loss of Werner amine) Vessential to the method of preparation heretofore employed.

I have made the unexpected discovery that the use of 'Werner complex solutions prepared by the method taught herein for clathration purposes results in a substantial increase in separation elciency over the use of comparative Werner complex solutionsmade by the previously used technique.

It is thus a principal object of my invention to provide an in situmethod of preparing a solution of a Werner complex in a primary solvent which avoidsthe necessity of having to separately synthesize the Werner complex and primarysolvent.

It is another object of the invention to provide a method of preparing a solution of a Werner complex in a primary solvent free of extraneous ions.

Still another object of the invention is to provide a method of preparing a solution of'av Werner complex in a primary solvent comprising an aqueous alkanolam'ine solution containing a dissolved alkanolammonium salt of the anion of the Werner salt whereby said alkanolammonium salt and said Werner salt are produced as coproducts in the same solution.

It is a more specific object of my invention to provide a method of preparing a solution of theWerner complex Ni(4MP)4(S.CN)2 in a primary solvent consisting of an alkanolamiue having nickelous thiocyanate dissolved therein by means of which the Werner salt is intermediately synthesized in such manner as to be free of extraneous ions such as ammonium and sulfate ions.

It is another object of the invention to prepare a Werner complex solution which when used for clathration purposes exhibits a substantial increase in separation etli- 3 ciency over that of any such solution made by previously known 'methods Other objects and features of this invention Will be readily apparent to those skilled in the art from the complete description thereof which follows.

Reference is now made to the accompanying drawings which.' illustrate in owsheet form the basic steps of the preparation of a Werner complex solution according to tliejn'ethod of my invention and a generalized method of clathiation utiliziir'xg said Werner complex solution;

Turning lirst to FIGURE 1, which is a diagrammatic representation of the preparation of a Werner complex solution by means taught herein, step (I) shows the mixing o f an aqueous solution of ammonium thiocyanate and ethah'olajaiej. For of brevity, ethanolamine is ablire'v'iatedl 331 (for monoetlianolamine) on FIG- URE L While FIGURE 1 is'lirited to the use of particular the invention isfnot restricted to Butis'hroadjenough to encompass' many other ingredients equvalentthreto for'iny The aqueons solution is introduced Ato step (I) 1f, in of a' solution of 50 percent is introduced through line 3 the and ammonium thio- Siidir rn'gs about the following reaction:

Per:

reactionifbet'wex :and the @mten emite' immane@ deze guagua ing affords a otk reinovi insmeren-empieza; mesonv (ammnnmouanfraemx-Hswnmand wm on' mmasnftaeis a @meer of NiCO, through line 5 as shown-'in step with the lVIEzBSmi-URNKSGNL. The maybe present.

it is' prsentnly conta'iiant whicli'can cause fudiicnltyifngt'rem'oyed, Toaccomplish such elimination- 'of C03 thegso on from mixing ste'p (III) is heated and reuxed, as shown at stcp- (IV). The solutio'n from islnormally. a concentrated. mixture wmnnenre' is then 'winidra'wn lingflq;

to primary solvent, the primary solvent consisting of a solution of ethanolarnmonium thiocyanate in a mixture of ethanolamine and Water. The mixing of the li-methylpyridine, and other components as needed, into the solution from step (IV) is shown as step (V) on FIGURE l. The mixture obtained from step (V) is a Werner complex solution suitable for use in clathration processes for the separation of ditiiculty separable compounds.

My method is not limited to the particular embodiment shown on FIGURE 1 insofar as steps (IV) and (V) are concerned. One possible alternative procedure, where the solution from step (IV) is aconcentrated mixture as is normally the case, is to add allot-'the MEA and water required for assurance ofvdesired concentration levels iu the final Werner complex solution fo said mixture prior to the addition of 4`methylpyr`idrie thereto. The solution from the step (IV) reluxingfdpe'ation is stable to storage whether or not it is with additional water and MEA and thus where immediate conversion of that material to a Werner 'complex solution i's not contemplated; it can'be 'stored either in its form or in' a' more diluted form, until needed for such purpose.' Y

Turning DCXLO FIGURE?, this drawing 'ShW'SbW diagram illustration of the use of a Werner complex's'olu-- tion made by the methodof this invention, for clathraition' purposes# gf..

In the' ci" 'on theeed to he resolved is introduced through lint? T Sm'akeup' Werner' com'- plex solution preparedby the netllod shown in 1 Vis introduced through line' 2 bulig'of 'the Werner and- 'fe pn; ase' frnopfe'ltnrued pnmary solvent phase froigl (VIII) fermava-.line 19t-marraine@ I which nie VSeite' entre@ non @mainstaywm 1s also transfe' Aiisnormnl solved in 'the'. nitrate frein mirarme@ bssefmiirthewernercmplxrfl xuef-m-eenver'tis Werner amine for reuse in the" system; variousf techniques have' been integrated with ranate step (VH1). In this connection. it. is knownto' employ a secondary solventwhich preferentially dissolves-the nonclathratable feed components an'dtheWerner aminefrom the filtrate, or an organic acid such as succinic acid, in such fashion as to elect a recovery of the Werner amine. Methods of so using these materials will be discussed in greater detail hereinafter.

A In elathrate dissolving step (IX), the solid clathrate 1s redissolved in the primary solvent phase by raising the temperature a suitable amount such as, for example, from about 56 to about 80 C. Upon dissolution of the clathrate, the clathrated component of the feed normally forms a separate liquid phase. This two-phase mixture is then transferred via line 23 to extract separation step (X), wherein the formerly clathrated feed components are separated by settling and decanting or any other desired method. Here again, as in the case of ratlinite separation step (VIII), additional means such as those employing a secondary solvent or an organic acid may be used in conjunction with or as a part of step (X) for recovery ot Werner amine (heterocyclic nitrogen base) dissolved in the extract product. The extract mixture of clathrated feed components is removed via line 25 as one product of the clathration separation operation (the other l0 product being the rainate removed from raffinate separation step (VIII) via line 17), and the Werner complex solution phase from extract separation step (X) is recycled through line 11 to clathration step (VI).

The Werner complexes prepared in solution according 15 to my novel method are made up of at least three components. The fundamental unit is a Werner salt, this being asalt of a metal having an atomic number above 12 which is capable of forming coordinate complexe of the Werner type. I have observed that divalent metals having incompletely lilled 3d or 4d electron shells are particularly amenable to Werner complex formation. Examples of some metals fitting this description are manganese, iron, cobalt, nickel, palladium and platinum, of which the first four are preferred because of their good performance characteristics, relatively low cost and ready availability.

The anion of the Werner salt may comprise any suitable negative radical, such for example as thiocyanate, isothiocyanate, azide, cyanate, isocyanate, cyanide, sulfate, nitrate. nitrite,A chloride, bromide, iodide, phosphate, formate, acetate, an'd the like. A group of negative radicals found'to be particularly eiective for the present puri poses consists of the monovalent anions, particularly the thiocyanate, isothiocyanate, azide, cyanate, isocyanate and cyanide radicals. However, any anion may be utilized, the salts ofwhich are capable of producing crystalline- Wrncr complexes bycoordinate bonding t'o the Wcrner hereinafter described. Such complexes are de-A scribed generally in Modern Aspects of Inorganic Chemis-V try, Emelius and Anderson, 'J9-489, Van Nostraud Coi., 40 1946, and also in Textbook of Inorganic Chemistry, vol.

X, M- M111 Sutherland, J. P. Lippincott Co., 1928;

j The second major component of the Wernercomplexes of one or more of the Werner amines.` Werner ,that term is employed herein, are normally heterocyclic nitrogen bases which are bound to'the central metal atomiof the Werner complex through coordinate bonds. The operative complexes are mainly of the tetraand hem-coordinate types, wherein the metal atom is conitrogen base shoul'd'bc selected so as to give a maximum selective absorption for the particular compound which is to be absorbed into the crystal lattice of the complex. For example, if it is desired to absorb p-rylene, a very suitable nitrogenib'a'se is methylpyridine Not "all nitrogen bases 55 are'equally ctective in forming complexes which will' absorb the component. For example, the i-methylpyridine complexwith nickel tliiocyanate is not as effective as the 4-metl1ylpyridine complex for absorbing p-xylene, presumably because of the stearic etects of the llt-methyl group. However, the 3methylpyridine complex may be used advantageously for absorbing other compounds. The nitrogen bases should therefore be selected by a iudicious combination of eoretical reasoning and actual. testing of the complexes 1th the particular mixture to be 65 separated. The overall molecular dimensions of the nitrogen base should preferably ap oximate the overall molecular size of the compound t be absorbed in the complex.

In general, any heterocyclic nitrogen base may be em- 70 ployed which is suiciently basic to form coordinate complexes with the above-described salts. This includes monocyclic and polycyclic compounds, wherein at least one of the heterocycles contains from one to three hetero-N atoms. ln over-all size, the nitrogen base may contain ordinated with four or six atoms of basic nitrogen. The Q from three to about thirty carbon atoms, preferably from four to fteen. interfering functional groups such as COOH should be absent, but other more neutral, relatively non-coordinating functional groups may be present such as halogen, hydroxyl, nitro, allroxy, aryloxy, amino, cyano, carboallroxy, alkanoyl, acetyl, etc., provided such functional groups are compatible with any functional groups present in the mixture of compounds to be separated. Examples of suitable bases include pyridine, substituted pyridines, substituted pyrroles, piperidines, substituted piperidines, and the like. x

A particularly preferred class of organic bases are the heterocyclic, resonance-stabilized bases 'which contain one to three, but preferably one, hetero-N atoms. Suitable examples are pyridine, the picolines, triazole, quinoline, the quinaldines, isoquinoline, pyrimidine, pyrazine, pyridazne, and substituted derivatives of such compounds. y 0f this preferred class, a sub-group which is particularly versatile and useful comprises the substituted pyridines, and especially the 4substituted, the 3-substuxted, and the 3,4-disubstituted pyridines. These compounds are suiciently strong bases to form relatively stable AWerner complexes, and the resulting complexes are capable of selectively forming clathrates' stablecat room temperatures with a wide variety of aromatic 'compounds Suitable substituted pyridines comprise the following: ,i-

' 3c11loropyridine"" 3hydroxypyridine 3methoxypyn -dine 1 3-acetylpyndm e Y l B cyanom mdm' e@ 1*.;1; i Ethylnicotinate t l 3,4-dimethylpyridine 3,4-diethylpyridine el Y v1 3metl1yl, 4ethylpyridine=` .Y 4methyl, 3-ethylpyridine 4-methyl, S-n-hexylpyridine' Y A-methyl, 3-cyanopyridine 4-chloro, S-methylpyridine A-acetyl, 3methylpyridine 4-methoxy, S-ethylpyridine Isoquinoline While, as indicated'above, the Werner amines suitable for use in the preparation of Werner complexes within the scope of this invention are normally heterocyclc nitrogen bas, it is not essential that this be the case and other nitrogen bases known to form Werner complexes suitable for purposes of my invention can be used in lieu of said heterocyclic bases if desired. Particularly exemplary of nitrogen bases, other than hetcrocyclic bases, suitable for C such purposes, are the substituted primary benzylamines having one or the other of the following general formulas:

te 11i-(EH Rz-H Cl (l wherein R1 is a primary alkyl group, R2 is H or a primary alkyl group and R3 is a neutral, relatively non-coordinating functional group such as alkyl, halogen, hydroxyl, nitro, alkoxy, aryloxy, cyano, carboalkoxy, alkanoyl, acetyl, etc., which is compatible with any functional groups .present in the mixture of compounds to be separated by the particular Werner complex under consideration; R3 may be either polar or not and it can be located on the ortho, meta or para position of the benzene ring. Some typical compounds fitting the above description are:

a-Methylbenzylamine a-'Ethylbenzylamine a-Propylbenzylamine @Butylbenzylamine m-Isobutylbenzylamine a-Amylbenzylamine a-Hexylbenzylamine a-Octylbenzylamine in-Methyl-p-methylbenzylamine a-Methyl-o-methylbenzyl'amine a-Methyl-p-ethyl'benzylamine a-Methylpisopropylbenzylamine a-Methyl-p-t-butylbenzylamine a-Methyl-ep-methoxybenzylamiue a-Methyl-p-fluorobenzylamine a-Methyl-p-chlorobenzylamine a-Methyl-ochlorobenzylamine a-Methyl-p-bromobenzylamhle a-Methykp-iodobenzylamine a-Methyl-m-nitrobenzylamine a-Propyl-p-methylbenzylamine lic-Propyl-p-bromobenzylamine z-Isobutyl-p-bromobenzylamine a-Methyl-p-cyclohexylbenzylamine p-Bromobenzylamine p-Dimethylaminobenzylamine Many other similar examples of suitable Werner amines could be gited, as will be apparent to those skilled in the art, and the complexes mayinclude only one such amine, r a mixture of two o r more may be employed, in which case a mixedlcompleir is formed.

The preferred Werner complexes-of monovalent anion salts of this invention may be designated by the following general formula:

Y. es

[Ni(4MP)4Br2] [Mn(4MP (SCN) 2] [Mn (isoquinoline) 4(SCN) 2] Obviously many other complexes similar to the above could be employed, not all of which would give optimum separation of all mixtures but which should be selected to meet the specitic peculiarities of the mixture concerned. The primary solvents employed herein contain water plus any suitable water-soluble organic or inorganic nitro gen base which is more strongly basic than the Werner amine. The ratio of nitrogen base to water will vary widely depending upon the Werner complex used and the particular nitrogen base. Generally, the primary solvent will contain between about 10% and 90% bygweight of nitrogen base. The ratio should be such asffo provide the desired diierentialsolubility of Werner complex therein, at the respective clatbration and declathration tem peratures. When using ammonia, suitable concentrations may range between about 10% and 30% by weight in the declathration step and about 0% to 20% in the clathration step. Operative concentrations of ethanolamine (NHzCHzCHgOH) may range between about 10% and 70% by weight in both stages. In all cases, it is preferred to use suicentvwater to render the feed mixture substantially insoluble in the primary solvent..

Other alkanolamines which may be used inplace of mono-ethanolamne include for example, dietlianolamin'e; triethanol'amine; 24amino-n-butanol'; 2amino2methyll propanol; 2-(methylamino)ethanol; 2'(etliylamino)eth anol; 2amino2`ethyl-l,3'propanediol; 2-an1ino-2metlyl 1,3-propanediol'; and the like. 1n general any limer;` alkanolamine containing from two to about ten carbon atoms, from one to three amino groups, and from one to three liydr'orylV groups may be employed, including primary, secondary, and tertiaryamines. The operative ratios of allcanolamine in the solvent may vary widely, eg., fromabout perc'cnt nol T5 percent by weight. Preferred ratios generally fall -tlie range from about l0 percent to about IU percent.f The' greater the concen-Y tration of alkanolamxne in the solvent, the greater willbe the solubility of 'Werner complex'and feed mixture-therein'.

Other volatile bases (Boiling below water)v which may be used in placebfahmoniaincludcfor example, methylamine,r dimethylamine, "t'inie'tliylamnei, 'metliyl-ethyla# mine, ethylamine, diethylamine, trietliylamine, n-propylamine, iscpropylamine, nlbutylanine, isobutylamine, soamylamine, and the like.

In gmieral, any water-soluble nitrogen base having a dissociation constant greater than about 10-5, and greater than the dissociation constant ofthe Werner amine, may be used as the alkaline component of the primary solvent.

The operating class of ammonium saltswhich may be used herein includes substituted, as well as unsubstitut'e'cl, ammonium salts. ASuitable ammonium salts are ammonium t'niocyanate,i ammonium chloride, `arruixonium sulfate, ammonium nitrate, ammonium acetate, ammonium citrate, ammonium osalateammonium glycolate, 'ammonium succinate, and the like'. Suitable substituted'ammonium salts include methyl ammonium tliiocyanate, dimethyl ammonium ,thiocyanate ethyl ammonium chloride; cthyl ammonium sulfate, ethanolammonium thiocyauate, ethanolammonium chloride, ethanolammonium sulfate, ethanolammonium cyanate, ethanolammonium cyanide, diethanolammonium thiocyanate, ethanolammonium acetate, and the like. These salts may be used in proportions ranging between about l% and 40% by weight of the primary solvent, depending upon relative solubilities. Any amounts are effective in some degree, and the preferred proportions generally range between about 15% and 30% by weight.

As previously indicated, it is preferred to use an ammonium salt, the anion of which is the same as the anion of the Werner salt. Since the preferred Werner salts are the thiocyanates, it is therefore preferred to use ammo- 9 nium thioeyanates. It is further preferred to use an ammonium salt of the same nitrogen base as that used in the primary solvent. Thus, where ethanolamine is used in the primary solvent, the preferred salt would be ethanolammonium thiocyanate.

The Werner complex solutions prepared by the method of my invention have particular utility in clathration procedures for separating feed mixtures of dicultly separable coznpounds such as, for example, mixtures of xylene isomers, one such procedure being depicted in generalized form on FIGURE 2.- As explained above in the description of that ligure, various techniques have been proposed either as a part of or in conjunction with ralinate separation step (VIII) in order to elect a re covery of dissolved Werner amine in the mixture. For example, a secondary solvent can be added at this point to preferentially dissolve Vthe non-clathratable feed components and Werner amine material present in the ltrate from step (VII). Where the feed mixture is composed of aromatic hydrocarbons, the secondary solvent can be a paraflinic or naphthenic hydrocarbon such as pentane, heptane, octane, nonane, or mixed hydrocarbons such as alkylate fractions. The solution of non-clathrated feed components in the secondary solvent is then withdrawn m the system and sent to a secondary solvent recovery step, which may befor example, a fractionalldistillation operation wherein secondary solvent plus lany dissolved Werner amine is distilled overhead and the non-clathrated.

feed components are recovered as bottoms. 'Ihe secondary solvent-Werner amine overhead product can be recirculated to admixtnre withinew filtrate, goingto ratiinate separation step (VIEL 1 I Y A secondary solvent technique can also be incorporated into extract separationstep (X) of FIGUREZ if desired. Thus such a secondarysolvent can be added at this point after which the solution of clathratedfeed components in the secondary solvent is removed 'andsent to a secondary solvent recovery step,which again maybe a fractionaldlstillation, wherein secondarysolvent plus dissolved Werner amine is distilled asan overhead which may, if de-` sired, be rccycledto the systennfand the formerly clatlirated oomponentsiarerccovered as a bottoms product- For a more detailed description of the use of a .secondary solvent for the purposes indicated above,see my co-pend ing U.S. patent application Serial No. 26,489, iled=May 3, 1960 and maturing to U.S .,',Patent No. 3,029,300.

Another technique` for the recovery of Werner amine from clathration process productstreams such as the ltrate Stream from tiltration step (VII) and the extract phase from step (lX) of FIGURE 2 employs an aqueous acid solvent, such ais-aqueous succinic acid, to accomplish this purpose. A detailed description of this particular technique can b` found in my co-pending-U.S. patent vapplication Serial No. 65,641,A tiled October 28,`1960. .-l A wide variety of feed mixtures can beresolvedbythe clathration method described above. Said'method isoperative for separating substantially any mixture of organic compounds wherein the ompofnents diifer in molecular:

coniiguraton, and wherein atdast one component-is substantially aromatic in character. By substantially aromatic is meant that at least about 20 percent of the car- ,bon atoms in the molecules to be clathrated are present as structural units of an aromatic ringfthe term aromatic having the meaning hereinafter specified. Any remaining carbon atbms may be present as saturated or unsaturated aliphatic side-chains, or saturated or unsatiirated non-aromataic ring systems. Such compounds may contain a total of from 4 to 60, and preferably from 6 to 20, carbon atoms. A

A difference in molecular configuration, as referred to herein, meansa dilerence in molecular size or shape as a result of differences in (l) the number of atoms per molecule, and/or (2) the arrangement of atoms within the respective molecules, and/ or (3) the size of the atoms present in the respective molecules.

Any number and type of functional groups may be present in the feed components, provided that such groups are compatible with the Werner complex employed, ie., that such groups do not change the chemical character of the Werner complex. Generally excluded are those compounds which are either so acidic as to decompose the Werner complex, or so basic asto displace the Werner amine from the Werner complex. When the compounds are too acidic or too basic, itis feasible to prepare neutral derivatives of such compounds, eg., salts, esters, others, amides, etc., and then effect separation of the neutral derivatives.

Whenever any mixture of compounds is so incompatible with the Werner complex that thel normal clathration procedures herein described result primarily in; chemical decomposition, change, or disruption of the Werner com-v plex, as opposed to the desired clathration, the contacting of such mixtures with the Werner complex is by definition excluded from the term clathration as used herein and in the claims. Functional groups which generally do not disrupt the normal clathration reaction, and may hence be present in the feed components-are as follows: E -Cl, -Br, L Nob aryl-NH3, 011, alkyl-OH, aralkyl-OH, 2CD, -CHOfK-CN, COOR, COIL -O-metal, -SR, -CONH-z, wherein R isa hydro` carbon radical. Many groups which are generally, though not always, disruptive and to be avoided are SH, aryl-OH, -COOIL alkyl-NH2, aralkyl-NHg, and the like, unless they are first convertedA to more nearly neutral derivatives.

Feed mixtures which lend themselves particularly well to separation by thesclathration procedure described above arexylene mixtures such as those containing as typical ingredients p-xylene, m-xylene, lol-xyleneA and ethylbenzene. prevouslyidentiled as a-ZS, percent solutionof 3 iii a priiay salvan: of water; ethsnlamineaiiethelmixtures which are separable by the clathratonV method of this invention' see my oo-pending (ILS.V application Bk).A 26,489, W U.S.Patel'1l'.N'-o i3029A3`oo. .1 j

In the description of FIGURE-'1, the am step was@ scribed as that of mixing an laqueous solution of' monium thiocyanate with ethanolamin Asfindi'catcd previously the methodis not to the use of'th'es'e.

ingredicntsand any suitable water-soluble nitrogen base,

such as, for example, any suitable alkanolamin, can be used in place of the ethanolamine if desired. Also,any

aqueous solution of an ammonium salt of anamon capable of forming asalt with a metal having ali'atont: v.

number above 12, and of 'suchiiature suchas, for example, ethanolammonium thio'cyanate.

In place of the nickel carbonate any salt of a metal' having an atomic number above 12, which metal is capable of forming relatively water-insoluble Werner complexes with Werner amines when in the form of its salt with the anion added in aqueous solution to step (I) of the FIGURE 1 method, and an anion having no stable existence as suchin the aqueous medium can be added to step (III) of said FIGURE 1 method. The preferred metal salts are the hydroxides and carbonatos of those divalent metals having incomplete 3d or 4d shells in their electronic configuration, and particularly the hydroxide and carbonate of nickel. Where nickelous hydroxide, or other equivalent metal hydroxide, is employed in place of the nickel carbonate in the FIGURE l method, the

My preferred Werner complex solution sienes/i to 30 C., treated with 58.5 g. (0.6 m.) of NMCHMJA H2O, then heated to l00 C. for l0 min. with stirring.

The mixture obtained was a dark blue solution that contained a trace of undissolved nickel hydroxide. Two Weight percent Filter-Cel, a diatomaceous earth powder, was added to the mixture and it was then filtered by means of a Buchner funnel employing filter paper. The filtrate was a clear deep blue solution of nickelous thiocyanate in the primary solvent, stable to storage at ambient temperatures and having the following composition:

Ni(SCN)2 0.6 Ethanolammonium thiocyanate l.4 Ethanolamine 1.63 Water 10.90

The filtrate of this example was a concentrate containing the proper ratio of N(SCN)2 to ethanolammonium thiocyanate for my preferred Werner complex solution but less than the total amounts of water and ethanolamine requisite to that solution.

EXAMPLE II This example describes the preparation of a Werner complex solution from the Example l concentrate and the separation of a xylene mixture therewith by clathration.

To a 300 ml. 3-necked flask equipped with a stirrer, thermometer and condenser was added 68 g. (0.064 g.- atom Ni++) of the nickel thiocyanate concentrate produced in Example I, together with 22.7 ml. ethanolamine,

29.0 ml. water and 24.0 g. (0.256 m.) of 4-methylpyrin dine. Addition of the 4-methylpyridine resulted in precipitation of a blue Werner complex solid. The mixture was heated to solution (69 C.) then 23 ml. of feed xylene added. The mixture was stirred and cooled to 5 C., held at 5 C. for 10 minutes, then filtered. The lter cake was washed with 45 ml. of isooctane.

The filter cake Washings were combined with the liltrate and the resulting mixture was allowed to form two phases, a hydrocarbon phase and an aqueous one. The hydrocarbon phase was separated and acid washed .to remove 4-methylpyridine and analyzed for xylene isomer distribution. The solid was decomposed in dilute hydrochloric acid and the released hydrocarbon phase was separated and analyzed for xylene isomer distribution. The analytical data are shown below:

Table l Analyses Recovery e P- iN- O- Etliyl- P- lvlxylene xylene xylene benzene xylene xylone 14. S 8l. 2 0. 6 3. 4 63. 0 30. 6 0. 3 6. l 95. (i 9. l Filtiate 0. 9 95. 8 0. 8 2. 5 4. 4 93. 9

eVol. percent isomer found in that phase. Handling losses were distributed equally between the two streams produced.

The data presented in the above table show that 95.6 percent of the entering p-xylene was recovered as 63 percent pure p-xylene and that 90.9 percent of the entering m-xylene was recovered as 95.8 percent pure m-xylene. These results are superior to those realized under the same conditions employing pre-formed solid Werner complex.

The Werner complex solution of this example was characterized as follows:

Solvent composition:

Component: Weight percent Water 45 Ethanolamine 38 Ethanolammonium thiocyanate i7 Solvent/Ni(4MP)4(SCN)2 (wt. ratio):3.0.

The weight ratio of Ni(4MP)4(SCN)2 to p-xylene for the clathration treatment of this example was 12 and the separation factor a was calculated to be 224. The value of the separation factor, as those skilled in the art appreciate, is a measure of separation efficiency, the higher the value the greater the eiciency. The separation factor is similar to a distillation alpha, its Value being derived in the following manner:

p-xylene in clathrate crystals/p-xylene in filtrate m-xylene in clathrate crystals/m-xylene in liltrate EXAMPLE III ln this example a Werner complex solution was prepared by the previously described method in which the Werner complex is separately synthesized and then added to the primary solvent. Nickelous sulfate and ammonium thiocyanate were dissolved in water and 4-methy1pyridine was added thereto to precipitate the Werner complex; N(4MP)4(SCN)2. The solid material was separated from the resulting slurry as a hydrous solid of approximately 30 percent by weight Water and air dried for several hours at ambient temperature in iinely divided condition.

The air-dried Ni(4MP)4(SCN)2 was dissolved, with the aid of heat, in a quantity of separately prepared primary solvent. The ingredient quantities were adjusted so as to yield a Werner complex solution having a solvent/Ni(4MP)4(SCN)2 weight ratio of 3.0 and a solvent composition as follows:

Component: Weight percent Water 48.5 Ethanolamine 33.7 Ethanolammonium thiocyanate 17.8

Table Il Analyses Recovery e P- M- 0- Ethyl- P- M- xylene xylene xylene hen pn@ xylene xylene e vYol. percent isomer found in that; phase. Handling losses wer distributed equally between the two streams produced.

The separation factor a for this example was found to be 101.

A comparison of the results of this example with those of Example II clearly points out the superiority of my new method over the pre-existing method for the preparation of Werner complex solutions.

Thus in Example II, 95.6% of the entering p-xylene was recovered as 63% pure p-xylene. By comparison, in the present example, although the recovery was fairly high, the purity of the product was only 49.4%. With respect to the m-xylene, it will be noted that whereas the purity of product is roughly the same in Example III as in Example II, the yield is only 83.9% in Example HI by comparison with a yield of 90.9% in Example H. Also to be 'noted is the fact that the value of a in Example Il was over twice that in this example.

EXAMPLE IV This example describes the preparation of a Werner complex solution of the same composition as that prewith 5.2 m; of 2-amino-2-methyl-l-propanol.

l pared in Example Il, utilizing nickelous carbonate as the source of Vnickel for the Werner complex.

To a one-liter 3-necked flask equipped with a stirrer, thermometer and reflux condenser (attached via a rubber tube to a graduated cylinder containing 900 ml. H2O) was added 370 g. of 53.5 percent aqueous NH4SCN solution (2.60 m., 197.9 g. NH4SCN) and 246 g. (4.03 rn.) of ethanolamine. The mixture was heated to reflux and reflux continued until evolution of ammonia essentially ceased (total retiux period was 33 min. at 11.2 C.). Titration of analiquot from the ammoniarreceiver showed that 99.2'percent of the theoretical quantity of ammonia had been removed.

The ethanolammonium thiocyanate solution was cooled to C., treated with 71.1 g. (0.6 m.) of nickelous carbonate, then heated to reflux and reflux continued until evolution of carbon dioxide essentially ceased (total reux period was lOminutes at 112 C.).

The mixture obtained contained traces of solid matter and two weight percent Filter-Cel, a diatornaceous earth powder, was added thereto and it was then ltered by means of a Buchner funnel employing filter paper. The ltrate was a clear deep blue solution of nickelous thiocyanatc in the primary solvent, stable to storage at ambient temperatures and containing as ingredients, besides the nickelou's thiocyanate, ethanolamrnonium thiocyanate, ethanolamine and water.

To a 300 ml. 3-nicked flask equipped with a stirrer, thermometer and condenser was added 68 g. of the aforesaid solution, 22.7 ml. of ethanolamine, 29.0 ml. of water o and 24.0 g. (0.256 m.) of 4-methyipyridine. This resulted in a Werner complex solution of nickel tetra(4methyl pyridine)dithiocyanate in a primary solvent consisting of water, 38% ethanolamine and 17% ethanolammonium thiocyanate. The concentration of Werner complex in the solution was 25% corresponding to a primary solvent/Werner complex weight ratio of 3.0. Using this solution to separate a mixture of xylenes such as that employed in Example 1I results in clathration separation results substantially equivalent to those set forth in Table l.

Following are additional examples of the preparation and utilization of various Werner complex solutions according to methods taught herein.

EXAMPLE V A quantity of 35 percent aqueous ammonium cyanide solution containing 2.6 m. of ammonium cyanide is mixed Upon admixture of the two liquids the following reaction takes place in the resulting solution:

The reaction mixture, now containing water, Z-amino- 2-methyll-propanolammonium cyanide and ammonia is retiuxed to expel the ammonia. To the retiuxed mixture free of ammonia there is added 0.7 m. of manganous carbonate which stoichiometrically reacts with a portion of the 2-amino-2-methyl-1-propanolamrnonium cyanide to yield a solution of 0.7 m. of Mn(CN)2 and 1.2 m. of,

VquinolineLCbI)2 in a primary solvent of the following composition:

Component: Weight percent Water 46 2-amino-2-methyl-l-propanol 40 2 amino 2 methyl 1 propanolammonium Vcyanide 14 A mixture of rn-cymene and mesitylene is subjected to selective clathration treatment with the'above-described Werner complex solution at a solvent/Werner complex weightratio of 3.0 as a result of which m-cymene is separated from mesitylene, most of the former being recovered as a raffinate.

EXAMPLE vt A quantity of 55% aqueous ammonium acetate solution containing 3 mois of ammonium acetate is mixed with 3.5 mois of Z-amino-n-butanol; upon admixture of the two liquids the following reaction takes place in the resulting solution:

NmOOCCH The reaction mixture, now containing water, 2-aminol-butanolammonium acetate and ammonia is retluxcd to expel the ammonia. To the retiuxed mixture, free of ammonia, there is added 0.9 m. of cobaltous hydroxide which stoichiometiically reacts with a portion of the 2- amino-l-butanolammonium acetate to yield a solution of 0.9 m. of cobaltous acetate and 1.2 m. of 2-amino-lbutanolammonium acetate in a 2-amino-n-butanol and water mixture. The solution is either stored until needed for conversion to a Werner complex solution or converted immediately to such a solution in the manner described below. y

To' the aforesaid solution is added 3.6 m. of 4-ethylpyridine together with sufficient water and 2-amino-nbutanol to yield a 20% solution of Co(4-ethylpyridine)4(CH3CO2)2 in a primary solvent of the following composition:

Component: Weight percent Water 50.0

2-aminonbutanol 3 8.8

2-amino-1-butanolammonium acetate 11.2

A mixture of o-ethyl toluene and p-ethyl toluene is subjected to selective clathration treatment with the abovedescribed Werner complex solution, at a solvent/Werner complex weight ratio of 3 as a result of which p-ethyl toluene is separated Vfrom o-ethyl toluene, most of the former being recovered in the extract product and most of the latter being recovered as a rainate.

EXAMPLE V11 The reaction mixture, now containing water, Z-(methylamino) ethanolammonium cyanate and ammonia 1s reuxed to expel the ammonia. To the reliuxcd mixture free of ammonia there is added 1 m. of ferrous carbonate which stoichiometrically reacts with a portion of the 2- (methylarnino) ethanolammonium cyanate to yield a solution of 1 m. of ferrous cyanate and 0.6 m. of 2- (methylamino) ethanolannnonium cyanate in a 2-methylamino) ethanol, water and carbon dioxide solution. The solution is reliuxed to expel C02 and then either stored until needed for conversion to a Werner complex solution or converted immediately to such a solution in the manner described below.

To the aforesaid solution is added 4 rn. of pyridine, together with sutiicient water and 2-(methylamino) ethanol to yield 20% solution of Fe(pyridine)4(CNO)2 in a primary solvent of the following composition:

Component: Weight percent Water 76.6 2-(methylamino) ethanol 20.0

Z-(methylamino) ethanolammonium cyanate EXAMPLE Vll A quantity 'of 50% aqueous ammonium thiocyanate solution containing 2.6 mols of ammonium thiocyanate is mixed with 2.6 m. of ammonium hydroxide in a 50% solution. No reaction takes place upon mixture of the two liquids and the resulting solution is a mixture of 2.6 m. of ammonium thiocyanate and 2.6 rn. of ammonium hydroxide in an aqueous solution.

To the mixture there is added 0.5 m. of platinous hydroxide which stoichiometrically reacts with a portion of the ammonium thiocyanate to yield a solution of 0.5 m. of platinous thiocyanate and 1.6 m. of ammonium thiocyanate in an ammonium hydroxide solution. The solution is either stored until needed for conversion to a Werner complex solution or converted immediately to such a solution in the manner described below. To the aforesaid solution is added 2 m. of 4-methoxy-3-ethylpyridine, together with suicient aqueous ammonium hydroxide solution to yield a 30% solution of Pt(4methoxy, 3-ethyl pyridine) 4(SCN)2 in a primary solvent of the following composition:

Component: Weight percent Water 55.6 Ammonium hydroxide 30.0 Ammonium thiocyanate 14.4

A mixture of tetralin and naphthalene is subjected to selective clathration treatment with the above-described Werner complex solution at a solvent/Werner complex weight ratio of 3 as a result of which naphthalene is separated from tetralin, most of the former being recovered in the extract product and most of the latter being recovered as a raffinate.

EXAMPLE 1X A quantity of 45% aqueous ethylammonium thiocyanate solution containing 2.6 m. of ethylammonium thiocyanate is mixed with 2 m. of n-propylamine. The resulting mixture contains Water, n-propylamine and ethylammonium thiocyanate. To this mixture there is added 0.4 m. of palladium hydroxide which stoichiometrically reacts with a portion of the ethylarnmonium thiocyanate to yield a solution of 0.4 rn. of palladium thiocyanate and 1.8 rn. of ethylammonium thiocyanate in an aqueous solution of n-propylamine and ethylamine. The solution is either stored until needed for conversion to a Werner complex solution or converted immediately to such a solution in the manner described below. To the aforesaid solution is added 1.6 m. of l-hexylamine, togther with sufficient water and n-propylamine to yield a 20% solution of palladium(1-hexylamine)4(SCN)z in a primary solvent of the following composition:

Component: Weight percent Water 75.0 n-propylarnine-l-ethanolamine 15.2 Ethylammonium citrate 9.8

EXAMPLE X A quantity of 50% aqueous ammonium chloride solution containing 2.6 rn. of ammonium chloride is mixed with 4.5 m. of diethanolamine. Upon admixture of the two liquids the following reaction takes place in the resulting solution:

HOCH2-CH2 HO CHT-C H2 NH -l- NltCl NHzCl -l- NH3 HOCHV- C Hq HO CH2- C H2 The reaction mixture, now containing Water, diethanolamine, diethanolammonium chloride and ammonia is reluxed to expel the ammonia. To the reflux mixture free of ammonia there is added 0.6 m. of nickelous carbonate which stoichiometrically reacts with a portion of the diethanolammonium chloride to yield a solution of 0.6 m. of nickelous chloride and 1.4 m. of diethanolammonium chloride in a diethanolamine, Water and carbon dioxide solution. The solution is refluxed to expel carbon dioxide and then either stored until needed for conversion to a Werner complex solution or converted immediately to such a solution in the manner described below.

To the aforesaid solution is added 2.4 1n. of 4-chloro, 3-methyl pyridine, together with suilicient water and diethanolamine to yield a 25% solution of Ni(4chloro, 3-methylpyridine)4-C12 in a primary solvent of the following composition:

Component: Weight percent Water 57.2

Diethanolamine 30.0 Diethanolammonium chloride 12.8

A mixture of durene and isodurene is subjected to selective clathration treatment with the above-described Werner complex solution at a solvent/Werner complex weight ratio of 3 as a result of which durene is separated from isodurene, most of the former being recovered in the extract product and most of the latter being recovered as a raflinate.

It will be apparent to those skilled in the art that a great number and variety of Werner complex solutions within the scope of this invention can be prepared by carrying out the method taught herein using different combinations of Vthe various solvents, salts and bases applicable for the ing mixture to drive ammonia therefrom, adding from about .Oll to about (2.3 molsiof nicke'lous' carbonate per mol of ethanolammonium thiocyariate thereinr to the mixture, heat treating the mixture 'toetect relatively rapid and substantially complete reaction betweenthe niclreious carbonate and ethanolammonium thiocyanate, dissolving 4-1nethylpyridine in the heat-treatedmixture and adding additional .water and ethanolamine thereto, the quantities of 4-methylpyridine, water and ethanolamine added being such as to assure a solution of from about to about 4() percent nickel'tetra-(4-rnethylpyridine)dithiocyanate in a primary solvent consisting of from about to about 6D percent water, from about 30 to about 5() percent ethanolamine and from about 10 to about 30 percent ethanolammonium thiocyanate; (2) admixing the Werner complex solution from step (1) with said xylene mixture while cooling the lmixture to eiiect precipitation of a solid clathrate of p-xylene and nickel tetra(4methyl pyridine)dithiocyanate; (3) separating the solid clathrate from the mixture leiaving'liquid behind; (4) separating said liquid into a raffinate phase and an aqueous primary solvent phase; (5) re-dissolving said solid clathrate in the aqueous primary solvent phase from step (4) at a temperature from about 25 to about 75 C. higher than the clathration temperature in step (2); and (6) separating the mixture into a Werner complex solution phase and an extract phase comprising a xylene mixture enriched in p-xylene.A Y

2; A method of .preparing a solution of'a Werner complex dissolved in a primary solvent, said solvent comprising an aqueous' nitrogen base solution having dissolved therein a minor proportion of a water-soluble ammonium Salt, comprising Vmixing a salt of a metal having an atomic number above 12 and an anion selected from the group consisting of hydroxide and carbonate with a stoichiometric excess of a solution of an ammonium salt of an anion `capable of forming asalt with a metal having an atomic number above 12, which latter salt Vis capable of forming relatively'water-insoluble Werner complexes with Werner amines, in an #aqueous nitrogen base solution, and 'adding a quantity of a Werner lamine to the Vresulting solution.V Y Y i 3. A method of preparing a solution of a Werner complex dissolved in a primary solvent, said solvent cornprising an aqueous alkanolamine solution having dissolved therein a minor proportion of a water-solublealkanolammonim salt, ci'iinprisin'g mixingan aqueous solution of"an"a'mmoniu`m salt of'an anion capable of forming a s alt with ainetal "having anv atomic number Vabove 12, which latter salt is cap-able of forming relatively waterins'oluble Werner complexes with Werner amines, with a Ystoichiomet'ric excess of alkanolamine, adding to the resulting solution less than a stoichiometric quantity of a salt' of a metal having an atomic number above l2 and an anion selected from the group consisting ofvhydroxide and carbonate, and amine to the solution.

Y 4. A method of preparing a solution of a heterocyclic nitrogen base Werner complex' dissolved in' aA primary solvent, said solvent comprising an aqueous alkanolamine solution having' dissolved therein a minor proportion of la salt material selected from the group consisting of the thiocyanates, isothiocyanates, cyanat'es, `i'socyanates, cyanides and azides of the alkanolamines, and mixtures thereof, comprising an aqueous :solution ofka salt material selected from the group consisting of ammonium thiocyanate, ammonium isotliiocyanate, ammonium cyanate, ammonium isocyanate, ammonium cyanide, ammonium azid'e and mixturesfthereof, with a stoichiometric excess of alkanolamine; adding less than the stoichiometric quantity of ya material selected from the group consisting of the hydroxides and carbonatos of manganese, iron, cobalt, and nickel, and mixtures thereof, to the resulting solution; and adding a quantity of a heterocyclic nitrogen base material selected from the group consisting adding a quantity *of a Werner of the pyridine ring compounds and mixtures thereof to the solution.

V5. A' method of preparing a Werner complex solution of nickel tetra (4methylpyridine)dithiocyanate in a primary solvent, said solvent comprising an aqueous lower alkanolamine solution having dissolved therein a minor proportion of lower alkanolammonium -thiocyanate, comprising mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine, Vadding less than a stoichiometric quantity of nickelous hydride to the resulting solution, and adding a quantity of 4-methylpyridine`to the resulting mixture.

6. A method of preparing a Werner complex solution of nickel tetra(4methylpyridine)dithiocyanate in a primary solvent, said solvent comprising an aqueous lower alkanolamine solutionV having dissolved therein a minor proportion of lower allranolammonium thiocyanate, comprising mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine, adding less than a stoichiometric quantity of nickelous carbonate Ato the resulting solution, and `adding a quantity of 4-methylpyridine to the resulting mixture.

7. The method of claim o wherein the lower alkanolamine is ethanolamvine. n

8,1m a selective clathration process `for the separation of ia mixture of organic compounds where the components of said mixture differ in molecular configuration and where at least one component of said mixture is clathratable, wherein the feed mixture to be resolved is contacted 'with a ysolution of a Werner complex dissolved in a primary solvent comprising an aqueous nitrogen base solution having dissolved therein a minor proportion of a water soluble ammonium salt, and clathration is effected by 'altering lthe environment ofy theresulting mixture to effect precipitation of solid Werner complex clathrate, the improvement which comprises preparing the solution of said Werner complex in'said primary solvent by mixing a salt of a metal having an atomic number above yl2 and an anion selected from the group consisting of hydroxide and carbonate, with a stoichiometric excess n of a solution of an'ammonium Salt of an anion capable of forming a saltwith aV metal having an atomic number above 12, which latter salt is capable of forming relatively water-insoluble Werner complexes with Werner aminesin an aqueous nitrogen base solution, and adding a quantity of a lWerner amine to the resulting solution.

y9;. In a selective clathration process for the separation of a mixture lof organic compounds .where the components of Vsaid mixture differ in molecular conli'guration and where at least one component of said mixture is clathratable, wherein the feed mixture to be resolved is contactedrwith a solution of a Werner complex dissolved in a Aprimary solvent comprising anaqueous alkanolamine solution having dissolved therein a minor proportion of a water soluble allnanolammonium salt and clathiration is elected by cooling the resulting mixture to effect precipitation Voit`- solid Werner complex clathrate;the improvement which comprises preparing the solution of said Werner complex in said primary solvent by mixing an aqueous solutionof an ammonium salt of an anion capable of forming a salt with a divalent metal having an incomplete'd shell, which latter salt is capable of forming relatively water-insolubley Werner complexes with Werner amines, with ahstoichiometrio excess of alkanolamine; adding less than a stoichiometric quantity of a salt of `a divalent metal having an incomplete d shell and an anion selected from the group consisting of hydroxide and carbonate to the resulting solution; and adding a quantity of a Werner amine to the solution.

Hl0. In a selective clathration process'ifor the separation of a mixture of organic compounds where the components of said mixture differ in molecular coniguration andwhere at least one componentV of said mixture is clathratable, wherein the feed mix-ture Vto be resolved is contacted with a solution of a Werner complex dissolved in a primary solvent comprising an aqueous alkanolamine solution having dissolved therein a minor proportion of a salt material selected from the group consisting of the thiocymates, isothiocyanates, cyanates, isocyanates, cyanides, and azides of the alltanolamines, and mixtures thereof, and clathration is eiiected by cooling the resulting mixture to etlect precipitation of solid Werner complex clathrate; the improvement of which comprises preparing the solution of said Werner complex in said primary sol- Vent by mixing an aqueous solution of a salt material selected from the group consisting of ammonium thiocyanate, ammonium isothiocyanate, ammonium cyanate, ammonium isocyanate, ammonium Cyanide, ammonium azide, and mixtures thereof, with a stoichiometric excess of allranolamine; adding less than a stoichiometric quantty of a material, selected from the group consisting of the hydroxides and carbonatos of manganese, iron, cobalt and nickel, and mixtures thereof, to the resulting solution; and adding a quantity of a heterocyclic nitrogen base material selected from the group consisting of the pyridine ring compounds and mixtures thereof to the solution.

l1. ln a selective clathration process for the separation of a mixture of organic compounds where the components of said mixture dider in molecular configuration and where at least one component of said mixture is clathratable, wherein the feed mixture to be resolved is contacted with a solution of a lower li-alkyl pyridine Werner complex of nickelous thiocyanate dissolved in a primary solvent comprising an aqueous lower alkanolamine solution having dissolved therein a minor proportion of lower alkanolammonium thiocyanate, and clathration is effected by cooling the resulting mixture to eilect precipitation of Werner complex clathrate; the improvement which comprises preparing the solution of said Werner complex in said primary solvent by mixing au aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine; adding less than a stoichiometric quantity of nickelous hydroxide to the resulting solution; and adding a quantity of a lower 1f-alkyl pyrdine to the solution.

12. In a selective clathration process for the separation of a mixture of organic compounds where the components of sm'd mixture diiier in molecular coniiguration and where at least one component oi' said mixture is clatinatable, wherein the feed mixture to be resolved is contacted with a solution of a lower 4-alkyl pyridine Werner complex of nickelous thiocyanate dissolved in a primary solvent comprising `an aqueous lower alkanolamine solution having dissolved therein a minor proportion of lower alkanolarnmonium thiocyanate, and clathration is etlected by cooling the resulting mixture to eiiect precipitation of Werner complex clathrate; the improvement which comprises preparing the solution of said Werner complex in said primary solvent by mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower allianolamine; `adding less than 'a stoichiometric quantity of niclrelous carbonate to the resulting solution; and adding a quantity of a lower 4-allzyl pyridine to the solution.

13. A method for resolving -a mixture of disubstituted benzene isomers including a para isomer which comprises (l) forming a Werner complex solution of nickel tetra 4rnethylpyridine)dithiocyanate in a primary solvent comprising an aqueous lower alkanolamine solution having dissolved therein a minor proportion of lower allranolammonium thiocyanate by mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine, adding less than a stoichiometric quantity of nickelous hydroxide to the resulting solution, and adding a quantity of 4-methylpyridine to the solution; (2) admixng said solution or" nickel tetra(4-methyl pyridine)dithiocyanate in said primary solvent with said mixture of disubstituted benzene isomers; (3) cooling the resulting mixture to effect precipitation of a solid clathrate of tetra(4-methypyridine)dithiocyanate with a portion of the mixture of disubstituted benzene isomers enriched in the para isomer; (4) separating unclathrated isomers from the resulting mixture; (5) redssolving said clathrate in the remaining aqueous lower alkanolamine solvent phase at a relatively high temperature thereby liberating said mixture of disubstituted benzene isomers enriched in the para isomers; and (6) separating the para isomer enriched disubstituted benzene mixture from the reconstituted Werner complex solution.

14. A method for resolving a mixture of disubstituted benzene isomers including a para isomer which comprises (l) forming a Werner complex solution of nickel (4- methylpyridine)dithiocyanate in a primary solvent comprising an aqueous lower alkanolamine solution having dissolved therein a minor proportion of lower alkanolammonium thiocyanate by mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine, adding less than a stoichiometric quantity of nickelous carbonate to the resulting solution, and adding a quantity of 4-methylpyridine to the solution; (2) admixing said solution of nickel tetra(4methylpyri dine)dithiocyanate in said primary solvent with said mixture of disubstituted benzene isomers; (3) cooling the resulting mixture to effect precipitation of a solid clathrate of tetra(4methylpyridine)dithiocyanate with a portion of the mixture of disubstituted benzene isomers enriched in the para isomer; (4) separating unclathrated isomers from the resulting mixture; (5) redissolving said clathrate in the remaining aqueous lower allranolamine solvent phase at a relatively high temperature thereby liberating said mixture of disubstituted benzene isomers enriched in the para isomer; and (6) separating the para isomer eniched disubstituted benzene mixtue from the reconstituted Werner complex solution.

15. The method of claim 14 wherein said lower alkanolamine is ethanolamine.

16. A method for resolving a feed mixture of organic compounds where the components of said mixture diier in molecular conguration and Where at least one component of said mixture is clathratable, which comprises (1) forming a Werner complex solution of nickel tetra(4- methylpyridine)dithiocyanate in a primary solvent comprising an aqueous lower alkanolamine solution having dissolved therein a minor proportion of Alower alkanolammonium thiocyanate by mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of lower alkanolamine, adding less than a stoichiometric quantity of nickelous carbonate to the resulting solution, and adding a quantity of 4-methylpyridine to the solution; (2) mixing the resulting solution with said feed mixture; (3) cooling the resulting mixture to eilect precipitation of a solid clathrate of at least one component of said feed mixture with said Werner complex; (4) separating said solid clathrate from the liquid phase; (5) recovering lthe clathrated feed component from said clathrate; and (6) recovering the non-clathrated feed component from the liquid phase of step (4).

17. A method of preparing a solution which is convertible to a Werner complex solution by the addition of a Werner amine thereto comprising mixing a salt of a divalent metal having an incomplete d shell and an anion selected from :the group consisting of hydroxide and carbonate with a stoichiometric excess of a solution of an ammonium salt of an anion capable of forming a salt with a divalent metal having an incomplete d shell, which latter salt is capable of forming relatively water-insoluble Werner complexes with Werner amines, in an aqueous nitrogen base solution.

18. A method of preparing a solution which is convertible to a Werner complex solution by the addition of a heterocyclic nitrogen base thereto comprising mixing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of alkanolamine and adding less than the stoichiometric quantity of a material selected from the group consisting of the hydroxides and carbonates of manganese, iron, cobalt and nickel, landV Inixtur'es thereof, to the resulting solution.

19, As a new composition of matter, a solution prepared by; miiing an aqueous solution of ammonium thiocyanate with a stoichiometric excess of alkanolamine and adding less than the s'ticliome'tric 'quantity of a Inaterial selected from the group consisting of the hydroxicles and Carbonates of'manganese, iron, cobalt and nickel, and miitures thereof, to tl'ie resulting solution. Y

20. The method of claim 18 Whereintle material selected from the group consisting of the hydroxides and carbonates of manganese, iron, cobalt and nickel is nickelous carbonate.

at References Cited inthe file 0f this patentA UNITED STATES PATENTS f 2,007,166 Hund et al July 9, 1935 2,876,227 Schaeffer YMar. 3, 1959 2,905,684 Schaeffer et al Sept. 22, 1959 2,905,730 Ray et al Sept. 22, 1959 3,013,091 Fleck et al Dec. 12, 1961 3,029,300 Schaeffer Apr. 10, 1962 OTHER REFERENCES Schaeffer: The Chemist Analyst, vol. 41, No. 3, pp. 57 and 59,Septern'ber 1952.V

(SEAL) f Attest;

ERNEST W. SWIDER Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION 'Patent No. 3, 161,694 December 15,. 1964 William D. Schaeffer It is hereby certified that error appears in the above numbered patent requiring correction and that the Said Letters Patent should read as corrected belo' Column 18, line 74, for "equavalency read equivalency column 20, line ll, for "hydride" read hydroxide 3 column 21, line 63, before "4-methylpyridin`e)" inser'i; an

opening parenthesis column 22, line 8, for "isomers" read isomer l Signed and sealed this 13th day of April 1965. 

3. A METHOD OF PREPARING A SOLUTION OF A WERNER COMPLEX DISSOLVED IN A PRIMARY SOLVENT, SAID SOLVENT COMPRISING AN AQUEOUS ALKANOLAMINE SOLUTION HAVING DISSOLVED THEREIN A MINOR PROPORTION OF A WATER-SOLUBLE ALKANOLAMMONIUM SALT, COMPRISING MIXING AN AQUEOUS SOLUTION OF AN AMMONIUM SALT OF AN ANION CAPABLE OF FORMING A SALT WITH A METAL HAVING AN ATOMIC NUMBER ABOVE 12, WHICH LATTER SALT IS CAPABLE OF FORMING RELATIVELY WATERINSOLUBLE WERNER COMPLEXES WITH WERNER AMINES, WITH A STOICHIOMETRIC EXCESS OF ALKANOLAMINE, ADDING TO THE RESULTING SOLUTION LESS THAN A STOICHIOMETRIC QUANTITY OF A SALT OF A METAL HAVING AN ATOMIC NUMBER ABOVE 12 AND AN ANION SELECTED FROM THE GROUP CONSISTING OF HYDROXIDE AND CARBONATE, AND ADDING A QUANTITY OF A WERNER AMINE TO THE SOLUTION.
 9. IN A SELECTIVE CLATHRATION PROCESS FOR THE SEPARATION OF A MIXTURE OF ORGANIC COMPOUNDS WHERE THE COMPONENTS OF SAID MIXTURE DIFFER IN MOLECULAR CONFIGURATION AND WHERE AT LEAST ONE COMPONENT OF SAID MIXTURE IS CLATHRATABLE, WHEREIN THE FEED MIXTURE TO BE RESOLVED IS CONTACTED WITH A SOLUTION OF A WERNER COMPLEX DISSOLVED IN A PRIMARY SOLVENT COMPRISING AN AQUEOUS ALKANOLAMINE SOLUTION HAVING DISSOLVED THEREIN A MINOR PROPORITON OF A WATER SOLUBLE ALKANOLAMMONUIM SALT AND CLATHRATION IS EFFECTED BY COOLING THE RESULTING MIXTURE TO EFFECT PRECIPITATION OF SOLID WERNER COMPLEX CLATHRATE; THE IMPROVEMENT WHICH COMPRISES PREPARING THE SOLUTION OF SAID WERNER COMPLEX IN SAID PRIMARY SOLVENT BY MIXING AN AQUEOUS SOLUTION OF AN AMMONIUM SALT OF AN ANION CAPABLE OF FORMING A SALT WITH A DIVALENT METAL HAVING AN INCOMPLETE D SHELL, WHICH LATTER SALT IS CAPABLE OF FORMING RELATIVELY WATER-INSOLUBLE WERNER COMPLEXES WITH WERNER AMINES, WITH A STOICHIOMETRIC EXCESS OF ALKANOLAMINE; ADDING LESS THAN A STOICHIOMETRIC QUANTITY OF A SALT OF A DIVALENT METAL HAVING AN INCOMPLETE D SHELL AND AN ANION SELECTED FROM THE GROUP CONSISTING OF HYDROXIDE AND CARBONATE TO THE RESULTING SOLUTION; AND ADDING A QUANTITY OF A WERNER AMINE TO THE SOLUTION.
 18. A METHOD OF PREPARING A SOLUTION WHICH IS CONVERTIBLE TO A WERNER COMPLEX SOLUTIN BY THE ADDITION OF A HETEROCYCLIC NITROGEN BASE THERETO COMPRISING MIXING AN AQUEOUS SOLUTION OF AMMONIUM THIOCYANATE WITH A STOICHIOMETRIC EXCESS OF ALKANOLAMINE AND ADDING LESS THAN THE STOICHIOMETRIC QUANTITY OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF THE HYDROXIDES AND CARBONATES OF MANGANESE, IRON, COBALT AND NICKEL, AND MIXTURES THEREOF, TO THE RESULTING SOLUTION.
 19. AS A NEW COMPOSITION OF MATTER, A SOLUTION PREPARED BY MIXING AN AQUEOUS SOLUTION OF AMMONIUM THIOCYANATE WITH A STOICHIOMETRIC EXCESS OF ALKANOLAMINE AND ADDING ELSS THAN THE STOICHIOMETRIC QUANTITY OF A MATERIAL SELECTED FROM THE GROP CONSISTING OF THE HYDROXIDES AND CARBONATES OF MANGANESE, IRON, COBALT AND NICKEL, AND MIXTURES THEREOF, TO THE RESULTING SOLUTION. 